Radical Islamic Terrorists use the internet for propaganda, radicalizing, recruitment, fund raising, and communication. ISIS/ISIL/IS is the worst of 'em right now, but there are plenty of others. Al Quada, Boko Haram, the Wahabis, and more.
We (the US and it's allies) ought to make a serious effort to drive them off the Internet. Their web sites ought to just disappear, their email should be intercepted, read, and discarded. Like wise their text messages. Facebook, Twitter, Instagram, Blogspot pages ought to self destruct. Plus anything else we can detect.
This is censorship, but I submit that censoring murderous terrorists is better than getting shot by them. And more effective than trying to take guns away from law abiding citizens.